This invention relates generally to thermo-optical devices.
A thermo-optical device is an optical device whose optical characteristics can be modified by heating. For example, the refractive index of a material may be selectively changed by heating. Examples of thermo-optic devices include tunable filters, lasers, variable optical amplifiers, and switches, to mention a few examples.
It is desirable that thermo-optic devices supply the least amount of power for heating the thermo-optic device to change its optical characteristics. Commonly, a waveguide is provided in a polymer filled region. The refractive index of the polymer filled region is changed by a heater. The tuning range is highly dependent on the effectiveness and efficiency of the heat delivered by the nearby heater.
Generally these schemes use a heater which is positioned over a polymer filled region. After long term thermal cycling, the heater may be subject to delamination due to the thermal mismatch between the polymer and the heater. The tuning range may also be unpredictable due to uncontrollable heat delivered to the polymer.
Thus, there is a need for other ways to provide thermo-optic devices.